JPH08316B2 - Powder pressure molding method - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention is an improvement of a powder pressure molding method in which powder is hydrostatically molded by a dry method. In the process of pressure molding, air in the powder is squeezed to a place where it does not adversely affect the molded product. It is about.

[Prior art]

Conventionally, powder pressure molding equipment that performs hydrostatic molding by the dry method is
As shown in FIG. 14, a mold 2 made of a flexible material (for example, neoprene rubber, urethane resin, etc.) and having a powder filling space 1 with a long axial length formed inside, and a powder filling space 1 Lids 3 and 4 for covering the upper and lower open ends 1a and 1b,
It is composed of a flexible pressurizing cylinder 5 to which the mold 2 is fitted, and a holding case 6 to which the pressurizing cylinder 5 is fitted. The pressurizing liquid is provided between the pressurizing cylinder 5 and the holding case 6. An annular pressure chamber 8 to which 7 is supplied is formed. The holding chamber 6 has a pressure chamber 8
The liquid supply / discharge ports 6c, 6d facing the are opened. The holding case 6 is formed with a through hole 6a penetrating in the vertical direction, and the pressurizing cylinder 5 is fitted in the through hole 6a. Between the upper and lower lids 3 and 4, a cored bar 9 which vertically penetrates the center of the powder filling space 1 has bolt portions 9a and 9b extending vertically, and the lid 3 The bolt portions 9a, 9b are inserted into the insertion holes 3a, 4a of the bolts 4, 4 and the nuts 10, 11 are tightened on the bolt portions 9a, 9b. The mold 2 is inserted into the pressurizing cylinder 5 from the through hole 6a of the holding case 6 while being covered with the upper and lower covers 3 and 4, and is screwed into the upper and lower openings 6e and 6f of the holding case 6. It is held by the tightened fasteners 12 and 13. Next, the usage of the conventional powder pressure molding apparatus configured as described above will be described according to the work procedure. First, the upper fastener 12 screwed to the holding case 6 is removed, and the mold 2 is pulled out from the holding case 6. The upper nut 10 and the lid 3 arranged above the mold 2 are removed, and the powder 14 is filled into the space 1 for filling the sentence structure. The upper end of the powder filling space 1 filled with the powder 14 is covered with the lid 3, and the core metal 9
Tighten the nut 10 to the bolt portion 9a of. Insert the mold 2 from the through hole 6a of the holding case 6 into the pressurizing cylinder 5,
The fastener 12 is tightened in the opening 6e of the holding case 6 to complete the preparation before pressurization. Next, in the pressure chamber 8 formed between the holding case 6 and the pressurizing cylinder 5, the liquid supply / discharge port of the holding case 6 is inserted.
A pressurized liquid 7 having a desired pressure is supplied from 6c and 6d. Although not shown in the figure, the flexible pressurizing cylinder 5 expands inwardly with the supply of the pressurizing liquid 7 and presses substantially the entire outer surface 2a of the mold 2 at the same time. The flexible mold 2 receives a pressing force from the pressurizing cylinder 5 to generate a mold inner diameter D.
The powder 14 in the powder filling space 1 is pressed at substantially the same time while decreasing The air intervening in the powder 14 increases in air pressure as the pressure of the pressurized liquid 7 rises.
The air passes through the air passage formed by 14 particle gaps toward the lids 3 and 4, and is discharged to the outside from the screwing gap between the bolts 9a and 9b of the cored bar 9 and the nuts 10 and 11. When the pressurization for a predetermined time has elapsed, the pressurized liquid 7 in the pressure chamber 8 is supplied to the liquid supply / discharge ports 6c and 6d.
Emitted from. Flexible mold 2 and pressure cylinder 5
Is naturally returned to the original mold inner diameter D by its own elastic force with the current pressure of the pressurized liquid 7. Subsequently, the upper fastener 12 screwed to the holding case 6 is removed, and the mold 2
Are removed from the holding case 6. Finally, mold 2
Molded product (not shown) and mold 2 obtained inside
And the core 9 are separated.

[Problems to be Solved by the Invention]

As described above, the air present in the powder 14 is the pressurized liquid 7
As the air pressure increases as the pressure rises,
It passes through the minute air passages in the powder 14 toward the lids 3 and 4, and is discharged to the outside from the gap between the bolt portions 9a and 9b of the cored bar 9 and the nuts 10 and 11. By the way, in order to quickly discharge the air intervening in the powder 14 and prevent the air from remaining, it is necessary that the air pressure is high and the air passage formed by connecting the particle gaps of the powder 14 is large. Is. In order to increase the air pressure, it is necessary to increase the pressure of the pressurized liquid 7. However, the air passage formed by the continuous particle gaps of the powder 14 becomes extremely narrow or closed due to the pressurization of the powder 14. Thus, increasing the air pressure and enlarging the air passage are contradictory matters. The conventional powder pressure molding method and molding apparatus are the same as those of the pressurized liquid 7
As a result, the entire molding pressure region of the mold 2 is pressed almost at the same time, and the mold inner diameter D is reduced.
As a result, in the conventional powder pressure molding method and molding apparatus, the pressure increase of the air in the powder 14 and the decrease or blocking of the particle gap of the powder 14 are simultaneously performed over the entire area of the powder filling space 1. As it progressed, it was not possible to solve the above trade-offs, and the following problems were caused. That is, when the lengthwise dimension H of the powder filling space 1 is increased, the powder 14 filled in the central portion of the powder filling space 1 reaches the gap between the bolt portions 9a, 9b of the core 9 and the nuts 10, 11. The compressed air in the high pressure state cannot be completely degassed due to the increased distance, and compressed air remains in the molded product. The compressed air remaining in the molded product causes damage to the molded product when it expands as the pressurized liquid 7 is decompressed. Therefore, in the conventional powder pressure molding method and molding apparatus, it is necessary to shorten the lengthwise dimension H of the powder filling space 1 to 500 mm or less in order to prevent compressed air from remaining. Couldn't get

[Purpose of the Invention]

In view of the above problems, an object of the present invention is to provide a powder pressure molding method capable of obtaining a long molded product without containing compressed air in the molded product.

[Means for solving problems]

The gist of the method of the present invention is to fill powder in a powder filling space having a long axial length formed inside a flexible pressure cylinder, and press the pressure receiving surface of the pressure cylinder with a pressurized liquid. In a powder pressure molding method for pressing a powder by pressing the powder into a powder by pressing, a method for pressurizing the pressure receiving surface of the pressurizing cylinder is as follows. The squeezed region of the body is sequentially expanded in time from the wall portion of the pressure cylinder corresponding to a part of the powder filling space to the wall portion of the pressure cylinder corresponding to the end of the powder filling space. This is to prepressurize the entire pressure receiving surface of the pressurizing cylinder and then simultaneously pressurize the entire pressure receiving surface of the pressurizing cylinder with high-pressure pressurized liquid.

[Work]

The operation of the present invention will be described with reference to FIGS. 3 (A) and (B) and FIG. 4 showing an embodiment. As shown in FIG. 3 (A),
The low-pressure pressurized liquid 7 is supplied to the pressurized liquid supply port 26 of the holding case 26.
It is supplied from c between the outer peripheral surface 25a which is the pressure receiving surface of the pressurizing cylinder 25 and the pressurized liquid guide surface 26f of the holding case 26. The low-pressure pressurized liquid 7 is initially applied to the outer peripheral surface 25a of the pressurizing cylinder 25 at a portion facing the pressurized liquid supply port 26c and the initial pressurizing region 2
5a-1 is formed, and the initial pressure area 25a-1 of the pressure cylinder 25 is expanded and deformed inward. The powder 14 in the powder filling space 1 is
Only the region of the pressure cylinder 25 corresponding to the initial pressure region 25a-1 is pressurized. In the space (not shown) in the pressurized powder 14, the air pressure increases as the powder 14 is pressurized,
It does not rapidly flow into the air passages formed by the interstices in the unpressurized powder and remain in the pressurized powder 14 in a compressed state. As the supply amount increases, the low-pressure pressurized liquid 7 flows out to the next pressurizing region adjacent to the initial pressurizing region 25a-1 of the pressurizing cylinder 25 as shown in FIG. 3 (B). , The expansion deformation of this next-stage pressure area is gradually expanded. The powder 14 filled in the powder filling space 1 is
The initial pressure is gradually applied toward the ends 1a, 1b (see FIG. 4) from the region in the powder filling space 1 facing the initial pressure region 25a-1 of the pressure cylinder 25. The air present in the powder 14 filled in the powder filling space 1 faces the initial pressurizing region 25a-1 of the pressurizing cylinder 25 as the powder 14 is sequentially pressed. It is squeezed from the region in the filling space 1 toward the ends 1a, 1b. As a result, the compressed air that causes damage to the molded product does not remain in the powder 14 that is initially pressurized. When the initial pressurization is completed, as shown in FIG. 4, the high-pressure pressurizing liquid 7 is supplied to the pressurizing liquid supply port 26c of the holding case 26.
From the outer peripheral surface 25a of the pressurizing cylinder 25 and the pressurized liquid guide surface 26f of the holding case 26, simultaneously pressurize the entire outer peripheral surface 25a which is the pressure receiving surface of the pressurizing cylinder 25, The powder 14 is pressure-molded at a predetermined final pressure.

[Explanation of the embodiment]

Next, a powder pressure molding method according to the present invention (hereinafter, referred to as “the present invention method”) will be described based on Examples shown in the drawings. (First Embodiment) FIGS. 1 to 5 show a first embodiment.
The powder pressure molding apparatus 20 for carrying out the method of the present invention comprises a pressurizing tool 21 and a pressurizing tool 22. The pressurized tool 21 has the same structure as the conventional one, and includes a flexible mold 2 having a vertically long powder filling space 1 formed therein, and upper and lower open ends 1a of the powder filling space 1. Lids 3 and 4 for covering 1b and a core metal 9 stretched between the upper and lower lids 3 and 4.
And nuts 10 and 11 screwed to the bolt portions 9a and 9b of the cored bar 9. The cored bar 9 has an appropriate cross-sectional shape such as a circular shape, an elliptical shape, or a polygonal shape, and one or a plurality of the cored bars 9 are stretched. When obtaining a solid molded product, the core metal 9 is not stretched in the mold 2. The improvement in the powder pressure molding device 20 is that the pressure tool 22
Is. The pressurizing tool 22 includes a pressurizing cylinder inside the holding case 26.
25 is inset. The holding case 26 has a rigid outer cylinder 23.
And an inner cylinder 24 that backs up the pressure cylinder 25, and upper and lower lids 2 that are screwed to the upper and lower ends of the outer cylinder 23 and hold the pressure cylinder 25.
8, 29 and an annular pressure chamber 27 between the outer cylinder 23 and the inner cylinder 24.
Are formed. The pressure cylinder 25 is made of a flexible material (for example, neoprene rubber, urethane resin, etc.), and its hardness is appropriately selected within the range of JIS rubber hardness of 40 to 90 degrees. Outer peripheral surface 25 that is the pressure receiving surface of the pressurizing cylinder 25
A is a pressure region, and the pressure region farthest from the ends 1a and 1b of the powder filling space 1 is the initial pressure region 25a-1. The holding case 26 has a pressurized liquid guide surface 26f that comes into close contact with the inner surface of the inner cylinder 24 and the outer peripheral surface 25a of the pressure cylinder 25.
Are formed. On the pressurized liquid guide surface 26f, an appropriate number of pressurized liquid supply ports 26c (see FIG. 2) facing the initial pressure region 25a-1 of the pressure cylinder 25 communicate with the pressure chamber 28. It has been opened. Above the pressurized liquid guide surface 26f, a suitable number of pressurized liquid supply / discharge ports 26g are provided at positions facing the lid 3 of the tool 21 to be pressed via the pressurizing cylinder 25. It is opened to communicate with 27. When the pressurized liquid guide surface 26f is located at the lower side, the lid body 4 of the pressurized tool 21 is interposed via the pressurizing cylinder 25.
A suitable number of pressurized liquid supply / discharge ports 26h are opened at positions opposed to the pressure chamber 27 so as to communicate with the pressure chambers 27. The upper and lower pressurized liquid supply / discharge ports 26g and 26h are the pressurized liquid guide surfaces of the holding case 26.
26f is provided as necessary in order to discharge the air interposed between the pressurizing cylinder 25 and the pressurizing cylinder 25.
The outer peripheral surface 25a is normally closed. Pressurized liquid supply / discharge port 2
Since the parts 25c and 25d of the pressurizing cylinder 25 that closes 6g and 26h are backed up by the lids 3 and 4 of the tool 21 to be pressed, the parts 25c and 25d are flexibly deformed (see FIG. 4). Keep closed until In the outer cylinder 23, the pressure chamber 27
The liquid supply / discharge ports 23a, 23b facing the are opened. The liquid supply / discharge ports 23a, 23b are connected to liquid supply / discharge pipes of a pressurized liquid supply / discharge device (not shown). The initial pressurizing region 25a-1 formed on the outer peripheral surface 25a of the pressurizing cylinder 25 is not limited to the central portion as shown in the illustrated embodiment, and although not shown, the three-dimensional shape of the molding target. Corresponding to, the upper end 25e and the lower end 25f of the pressurizing cylinder 25
Of course, it is also possible to select an appropriate local portion located between and. In the illustrated embodiment of the powder pressure molding device 20, the long axis of the powder filling space 1 coincides with the vertical direction, but the present invention is not limited to this and the illustration is omitted. Of course, the body filling space 1 may have a long axis inclined or horizontal. Next, an example of the method of the present invention will be described based on the procedure of using the powder pressure molding apparatus 20. First, as shown in FIG. 1 and FIG. 2, a pressurized tool 21 in which the powder 14 is filled in the powder filling space 1 is prepared. The pressurized tool 21 is inserted into the pressurizing tool 22, and is held at a predetermined position by the upper and lower tightening tools 12 and 13 screwed to the pressurizing tool 22. Next, the pressurized liquid 7 (for example, oil, glycerin, boric acid water, etc.) supplied from the pressurized liquid supply device (not shown) is supplied to the pressure chamber via the liquid supply / discharge ports 23a, 23b of the outer cylinder 23. Inflow to 27. Pressurized liquid 7 in pressure chamber 27
At a predetermined pressure (for example, 50 to 200 kg / cm ² ) flows out from the pressurized liquid supply port 26c of the holding case 26 and guides the outer peripheral surface 25a of the pressurizing cylinder 25 and the pressurized liquid of the holding case 26. Enter between surface 26f. Since the liquid supply / discharge attempts 26g and 26h formed near the top and bottom of the inner cylinder 24 are firmly closed by the portions 25c and 25d of the pressurizing cylinder 25, the pressurizing liquid 7 is discharged from the pressurizing cylinder 25. It will not be drained towards. As shown in FIG. 3 (A), the low pressure pressurizing cylinder 7 has an initial pressurizing region 25a-at a portion of the outer peripheral surface 25a of the pressurizing cylinder 25 facing the pressurized liquid supply port 26c.
1 is formed, and the initial pressure area 25a-1 of the pressure cylinder 25 is inflated and deformed inward. In the mold 2, only the outer peripheral surface 2a of the region facing the initial pressure region 25a-1 of the pressure cylinder 25 is pressed, the mold inner diameter D is reduced, and the powder 14 is pressed. The air (not shown) in the pressurized powder 14 rapidly flows out to the air passage formed by the large particle gap in the unpressurized powder because the air pressure rises, and the pressure is increased. Powder
It does not remain in the compressed state in 14. As the amount of supply of the pressurized liquid 7 increases, the pressurized liquid 7 flows out to the next pressure region adjacent to the initial pressure region 25a-1 of the pressure cylinder 25, as shown in FIG. The expansion and deformation of the next pressurization region will be gradually expanded. The powder 14 filled in the powder filling space 1 is moved from the region in the powder filling space 1 facing the initial pressurizing region 25a-1 of the pressurizing cylinder 25 to the end portions 1a, 1b (see FIG. 1). The pressure is sequentially increased toward (see). The air present in the powder 14 filled in the powder filling space 1 faces the initial pressurizing region 25a-1 of the pressurizing cylinder 25 as the powder 14 is sequentially pressed. From the area inside the filling space 1 to the ends 1a, 1b (first
Bolts 9a, 9 of the cored bar 9
It is discharged from the screwing gap between b and nuts 10 and 11 to the outside. As a result, compressed air that would damage the molded product A (see FIG. 5) does not remain in the pressed powder 14. The pressurized liquid 7 supplied between the entire outer peripheral surface 25a of the pressurizing cylinder 25 and the pressurized liquid guide surface 26f of the holding case 26 has a predetermined final pressure (for example, as shown in FIG. 4). 500 ~
The pressure is increased to 5,000 kg / cm ² ) and the powder 14 is pressed.
The pressurized liquid 7 in the pressure chamber 27 is decompressed after the pressure molding for a predetermined time. As shown in FIG. 5, the flexible mold 2 and the pressurizing cylinder 25 spontaneously return to the original mold inner diameter D due to their own elastic force as the pressurizing liquid 7 is depressurized. The pressurized tool 21 is extracted from the holding case 26 after removing the upper fastening tool 12 screwed to the holding case 26. The pressurized tool 21 includes nuts 10 and 11 arranged vertically.
Then, the lids 3 and 4 are removed, and the molded product A, the core metal 9 and the mold 2 are separated. (Second Embodiment) FIG. 6 shows a powder pressure molding apparatus 30 of the second embodiment. The present embodiment device 30 of the second embodiment is largely different from the powder pressure molding device 20 of the first embodiment in that the holding case
This is a point in which the pressurizing cylinder 25 is fitted inside the outer cylinder 33 of the steel body constituting the 36. The outer cylinder 33 has an inner peripheral surface facing the outer peripheral surface 25a of the pressure cylinder 25 as a pressurized liquid guide surface 36f. Outer cylinder 33
In the pressurized liquid guide surface 36f of, the initial pressurizing area 2 of the pressurizing cylinder 25 is
An annular distribution groove 33d facing the entire circumference of 5a-1 and the pressurizing cylinder 25
The annular distribution groove 33e facing the upper side of the outer peripheral surface 25a and the annular distribution groove 3 facing the lower side of the outer peripheral surface 25a of the pressure cylinder 25.
3f and is recessed. Pressurized liquid supply / discharge ports 33c, 33a, 33b are opened in each of the distribution concave grooves 33d, 33e, 33f. A pressurized liquid supply / discharge device 40 for supplying / discharging the pressurized liquid 7 to / from the powder pressure molding device 30 will be described. The initial pressurizing pump 41 and the booth pump 42 have suction ports 41a, 42a facing the oil tank 43. The discharge port 41b of the initial pressurizing pump 41 is connected to the pressurized liquid supply / discharge port 33c of the outer cylinder 33 via the check valve 44 and the solenoid valve 45. A pressure switch 46 and a relief valve 47 are connected between the discharge port 41b of the initial pressurizing pump 41 and the check valve 44. The discharge port 42b of the booth pump 42 is connected to the inlet port 48a of the boost cylinder 48 and the relief valve 50. The discharge port 48b of the boost cylinder 48 is connected to the solenoid valve 45 via a check valve 51. A pressure switch 52 is connected between the discharge port 48b of the boost cylinder 48 and the check valve 51. The operation circuit 53 for starting and stopping the initial pressurizing pump and the booth pump 42 starts only the initial pressurizing pump 41 until the pressure switch 46 for initial pressure setting outputs the set pressure detection signal, and the pressure switch 46 outputs. When receiving the set pressure detection signal, the initial pressurizing pump 41 is stopped and the booth pump 42 is started. Furthermore, the operation circuit 53
Activates the booth pump 42 until the pressure switch 52 for high pressure setting outputs a setting detection signal.
The booth pump 42 is stopped when it receives the set pressure detection signal output by. The drain pipe 63 communicating with the oil tank 43 is connected to the pressurized liquid supply / discharge port 33b of the outer cylinder 33 via the solenoid valve 54, and the pressurized liquid of the outer cylinder 33 via the solenoid valves 55 and 56. It is connected to the supply / discharge port 33a. A liquid level detection switch 57 is provided in the oil tank 43. The drainage device 64 forcibly discharges the pressurized liquid 7 remaining between the pressurized liquid guide surface 36f of the outer cylinder 33 and the outer peripheral surface 25a of the pressurized cylinder 25. Discharge port of compressed air source 58
58a is connected between the solenoid valves 55 and 56 via solenoid valves 59 and 60. A silencer 62 is connected between the solenoid valves 59 and 60 via a solenoid valve 61. The silencer 62
Since the pressurized liquid 7 may be discharged, the discharge port is preferably communicated with the oil tank 43. Next, the operation of the powder pressure molding device 30 in the second embodiment will be described together with the operation of the pressurized liquid supply / discharge device 40 and the operation of the liquid discharge device 64. First, the pressurized tool 21 filled with the powder 14 is loaded inside the outer cylinder 33. The pressurized liquid supply / drainage device 40 closes the solenoid valves 54, 55, 56, and the solenoid valve 45.
open. The initial pressurizing pump 41 is activated by the output signal of the operation circuit 53 to supply the pressurized liquid 7 to the pressurized liquid supply / discharge port 33c of the outer cylinder 33. The pressurized liquid 7 is the outer peripheral surface 25 of the pressure cylinder 25.
Enter between a and the pressurized liquid guide surface 36f of the holding case 36,
The powder 14 filled in the powder filling space 1 is loaded into the pressure cylinder.
Sequential pressurization is performed so as to squeeze toward the end portions 1a and 1b from a region in the powder filling space 1 facing the initial pressure region 25a-1 of 25. The air in the powder 14 is squeezed to the ends 1a, 1b in the powder filling space 1 by this sequential pressurization. The discharge pressure of the initial pressurizing pump 41 increases when the initial pressurization of the entire powder 14 is completed. The pressure switch 46 outputs a set pressure detection signal to the operation circuit 53 in accordance with the increase in the discharge pressure, stops the initial pressurizing pump 41, and activates the booth pump 42. The booth pump 42 supplies the high-pressure pressurized liquid 7 between the outer peripheral surface 25a of the pressurizing cylinder 25 and the pressurized liquid guide surface 36f of the holding case 36 to press-form the powder 14. . When the high-pressure pressurized liquid 7 reaches a predetermined pressure, the pressure switch 52 outputs a set pressure detection signal to the operation circuit 53 and stops the booth pump 42. If the specified time has elapsed since the booth pump 42 was stopped, the solenoid valve
45 is closed and solenoid valves 54, 55 and 56 are opened.
Most of the pressurized liquid 7 between the outer peripheral surface 25a of the pressurizing cylinder 25 and the pressurized liquid guide surface 36f of the holding case 36 flows through the drain pipe 63 due to the elastic return of the pressurizing cylinder 25 and the mold 2. It passes and returns to the inside of the oil tank 43. The liquid level detection switch 57 arranged in the oil tank 43 detects the return of the pressurized liquid 7.
Note that the pressurized liquid 7 may slightly remain between the outer peripheral surface 25a of the pressurizing cylinder 25 and the pressurized liquid guide surface 36f of the holding case 36 due to drain pipe resistance or the like. When the pressurized liquid 7 remains, the pressurizing cylinder 25 continues to press the mold 2, so that it becomes difficult to pull out the mold 2 from the pressurizing cylinder 25. The pressurizing liquid 7 remains in the pressurizing cylinder 25.
This is especially noticeable when the axial length of is long. Therefore, the drainage device
Activating 64 to forcefully drain residual pressurized liquid. The operation procedure of the drainage device 64 is as follows. The solenoid valves 59, 60, 61 are closed in advance. The oil tank
Based on the detection signal of the liquid level detection switch 57 arranged in 43,
Close solenoid valve 56 and solenoid valve 5
Open 9,60. Then, the compressed air supplied from the compressed air supply source 58 passes through the solenoid valves 60, 59, 55 and the pressurized liquid supply / discharge port 33a, and the outer peripheral surface 25a of the pressurizing cylinder 25 and the holding case 36 are heated. The pressurized liquid 7 that has flown out between the pressurized liquid guide surface 36f and remains is pressed. The pressed pressurized liquid 7 passes through the pressurized liquid supply / discharge port 33b, the solenoid valve 54 and the drain pipe 63 below and is quickly returned to the oil tank 43. When the return of the pressurized liquid 7 is completed, the solenoid valve 60 is closed and the solenoid valve 61 is opened, and the outer peripheral surface 25a of the pressurizing cylinder 25 and the pressurized liquid guide surface 3 of the holding case 36 are closed.
The compressed air remaining between 6f and 6f is discharged to the outside. When the discharge of the residual pressurized liquid is completed, the pressurizing tool 21 is pulled out from the pressurizing cylinder 25, and then the mold 2 and the molded product (not shown) are separated. (Third Embodiment) FIGS. 7 and 8 show the powder pressure molding apparatus of the third embodiment.
70 is shown. Powder pressure molding apparatus 70 of the third embodiment
Is largely different from the powder pressure molding device 30 of the second embodiment in that the seal structures 81, 8 near the upper and lower ends of the pressure cylinder 75 are provided.
2 and a protective cylinder 77 is interposed between the pressurizing cylinder 75 and the mold 2. The seal structure 81 near the upper end of the pressurizing cylinder 75 is
As shown in the figure, the upper edge 75e of the pressurizing cylinder 75 is fitted into the annular groove 85 formed in the lid 83, and the outer peripheral surface of the upper edge 75e is fitted.
The seal ring fitting groove 86 is provided on the 75a side, and the seal ring 87 fitted in the seal ring fitting groove 86 is brought into close contact with the inner peripheral surface 85a of the annular groove 85, and the inner depth 85b of the annular groove 85 is formed. Has an upper edge 75
It is the backup part of e. The seal structure 82 (see FIG. 7) near the lower end of the pressurizing cylinder 75 has the same structure as the seal structure 81 near the upper end. The protection tube 77 is made of a flexible material (for example, neoprene rubber, urethane resin, etc.),
The pressure cylinder 75 is protected by breaking the contact between the lid bodies 3 and 4 of the tool 21 to be pressed and the pressure cylinder 75. 9 (A) and 9 (B) show another embodiment of the seal structure of the pressurizing cylinder 75 near the upper and lower ends. In the seal structure 91, the upper edge portion 75e of the pressurizing cylinder 75 is fitted inside the annular groove 85 formed in the lid 83, and the seal ring fitting groove is formed on the inner peripheral surface 85a of the annular groove 85. 96 is recessed, and a seal ring 97 having an appropriate shape such as an O-shaped, V-shaped, or X-shaped cross section fitted in the seal ring fitting groove 96 is closely attached to the upper edge portion 75e of the pressurizing cylinder 75 to form an annular shape. The inner depth 85b of the groove 85 serves as the back-up portion of the upper edge 75e. 10 (A) and (B) show another embodiment of the seal structure of the pressurizing cylinder 75 near the upper and lower ends. In the seal structure 101, the upper edge 75e of the pressurizing cylinder 75 is fitted inside the annular groove 85 formed in the lid 83, and the outer peripheral surface 75a of the upper edge 75e and the annular groove 85 are Seal ring fitting groove on the peripheral surface 85a
108 and 109 are recessed to face each other, and both seal ring fitting grooves 1
The seal ring 107 fitted in the 08, 109 is in close contact with the bottom surfaces 108a, 109a of the seal ring fitting grooves 108, 109, and the inner depth 85b of the annular groove 85 is the back-up portion of the upper edge 75e. (Fourth Embodiment) FIGS. 1 and 12 show the powder pressure molding apparatus of the fourth embodiment.
It shows 110. The powder pressure molding apparatus 110 is one in which the powder filling space 1 is formed by the inner peripheral surface 117j of the pressure cylinder 117. (Fifth Embodiment) FIG. 13 shows a powder pressure molding apparatus 120 of the fifth embodiment. The powder pressure molding device 120 has a bottomed mold 1
21 is a pressurizing cylinder 127 fitted on the outside. The holding case 126 into which the pressurizing cylinder 127 is fitted is provided with an annular distribution groove 12 near the upper and lower ends of the pressurized liquid guide surface 126f formed on the inner circumference of the outer cylinder 123.
3e and 123f are recessed. Pressurized liquid supply / discharge ports 123a, 123b are opened in each of the distribution concave grooves 123e, 123f. The lid body 124 that covers the mold 121 is provided with a pressurized air discharge hole 124a if necessary. Next, the operation of the powder pressure molding device 120 will be described. First, the flexible mold 121 is fitted into the flexible pressurizing cylinder 127 while the powder filling space 1 inside is filled with the powder 14, and the upper end opening is covered with the lid 124. Is covered with. Next, the pressurized liquid 7 is supplied to the lower pressurized liquid supply / discharge port 123b. The pressurized liquid 7 supplied is the outer peripheral surface 127 of the pressurizing cylinder 127.
Pressurize b from bottom to top. Mold 121
Are sequentially pressurized from the lower side to the upper side by the sequential pressurization of the pressurizing cylinder 127. Powder 1 filled in the mold 121
4 is sequentially pressed from the bottom portion 1b to the upper end portion 1a in the powder filling space 1 by the sequential pressing of the mold 121. The air present in the powder 14 is accompanied by the sequential pressurization of the powder 14,
From the bottom region in the powder filling space 1 toward the upper end 1a, the powder is squeezed and discharged from the pressurized air discharge hole 124a of the lid 124 to the outside. In addition, when the lid 124 does not have the pressurized air discharge hole 124a, the air present in the powder 14 is the powder filling space 1
It is squeezed to the upper end portion 1a inside and separated from the powder 14. As a result, compressed air that would damage the molded product does not remain in the pressed powder 14. The pressurized liquid 7 supplied between the entire outer peripheral surface 127a of the pressure cylinder 127 and the pressurized liquid guide surface 126f of the outer cylinder 123 is further pressurized to a predetermined final pressure to press the powder 14. Mold. The pressurized liquid 7 is decompressed after the pressure molding for a predetermined time. The flexible mold 121 and the pressurizing cylinder 127 naturally return to the original inner diameter due to their own elastic force as the pressurizing liquid 7 is depressurized. Finally, the lid 124 is removed from the mold 121 to obtain a solid molded product (not shown). (Other Examples) In each of the above-described examples, the inner peripheral surface 2j of the mold 2 (see FIG. 1), which is the powder pressure molding surface, and the mold 121 (thirteenth embodiment) are used to obtain a cylindrical or columnar molded product. The inner peripheral surface 121j (see the drawing) and the inner peripheral surface 117j of the pressurizing cylinder 117 (see FIG. 11) are all circumferential surfaces. However, the shape of the powder pressure molding surface is
Although not shown, the inner surface is not limited to the circumferential surface, and various inner surface shapes are possible according to the three-dimensional shape of the molding target. Further, in each of the above embodiments, the pressurizing cylinder 25 (see FIG. 1), the pressurizing cylinder 75 (see FIG. 7), the pressurizing cylinder 117 (see FIG. 11).
The outer peripheral surfaces of the pressurizing cylinder 127 (see FIG. 13) and the pressurizing cylinder 127 (see FIG. 13) are circumferential surfaces. However, the outer surface of the pressurizing cylinder is not limited to the circumferential surface, and although not shown, various outer surface shapes are possible so as to obtain the molding pressure corresponding to the three-dimensional shape of the molding object. Is.

As described above in detail, the present invention has the following excellent effects. According to the present invention, the air in the powder filled in the powder filling space can be squeezed to the end of the powder filling space that does not substantially affect the molded product. Is not included. According to the present invention, the powder and the compressed air can be completely separated from each other, so that the molded product is not damaged at the time of demolding. According to the confirmation test by the present inventor, the ceramic powder was pressure-molded to have an outer diameter of 300 mmφ, an inner diameter of 240 mmφ, and a length of
It was possible to obtain a hollow molded product of 4,000 mm. As is clear from this confirmation test, the present invention makes it possible to obtain a long molded article which has been impossible in the past.

[Brief description of drawings]

1 to 5 show a first embodiment of a powder pressure molding apparatus for carrying out the method of the present invention, wherein FIG. 1 is a longitudinal sectional view and FIG. 2 is a sectional view of FIG. A cross-sectional view taken along line II-II, FIGS. 3 (A) and (B) are enlarged vertical cross-sectional views of an essential part in an initial pressure state, and FIG. 4 is a vertical cross-sectional view showing a final pressure state, FIG. Is a vertical sectional view showing the demolded state, and FIG. 6 is on the left side,
A vertical sectional view of the second embodiment of the powder pressure molding apparatus for carrying out the method of the present invention is shown, omitting the space between the upper and lower sides and the central portion, and the pressurized liquid feeding / discharging device and the discharging device are disposed in other parts. FIG. 7 is a schematic view of a liquid apparatus, and FIGS. 7 to 10 show a third embodiment of the powder pressure molding apparatus for carrying out the method of the present invention, and FIG. FIG. 9 is an enlarged vertical sectional view of the sealing structure of the pressurizing cylinder, and FIG.
(B) is an enlarged view of another embodiment of the sealing structure of the pressurizing cylinder, wherein (A) is a vertical sectional view in a non-pressurized state, and (B) is a vertical sectional view in a pressurized state. FIGS. 10 (A) and 10 (B) are enlarged views of still another embodiment of the sealing structure of the pressurizing cylinder. FIG. 10 (A) is a longitudinal sectional view in a non-pressurized state, and FIG. Is a vertical cross-sectional view of a pressurized state, FIGS. 11 and 12 show a fourth embodiment of the powder pressure molding apparatus for carrying out the method of the present invention, and FIG. 11 is a vertical cross-sectional view. , Fig. 12 shows XII in Fig. 11
Fig. 13 is a transverse sectional view taken along the line -XII, Fig. 13 is a longitudinal sectional view showing a fifth embodiment of the powder pressure molding apparatus for carrying out the method of the present invention, and Fig. 14 is a conventional powder pressure molding apparatus. FIG. 1 ... Powder filling space, 2 ... Mold 3,4 ... Lid, 25 (75) ... Pressurizing cylinder 25a ... Outer peripheral surface, 25a-1 ... Initial pressurizing area 26 (36, 126) ... ... Holding case 26f (36f, 126f) ... Pressurized liquid guide surface 26c ... Pressurized liquid supply / discharge port

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 54-81572 (JP, A) JP 505415 (JP, B1) JP 57-48317 (JP, B2) JP 54- 44305 (JP, Y2) Jikkyohei 3-57353 (JP, Y2)

Claims (1)

[Claims] 1. A method for filling powder in a powder filling space having a long axial length formed inside a flexible pressure cylinder and pressurizing a pressure receiving surface of the pressure cylinder with a pressure liquid. Thus, in the powder pressure molding method in which the pressure cylinder is squeezed to press mold the powder, as a method of pressurizing the pressure receiving surface of the pressure cylinder, a low pressure liquid is used.
The squeezing area of the pressurizing cylinder is temporally changed from a wall portion of the pressurizing cylinder corresponding to a local portion of the powder filling space toward a pressurizing cylinder wall portion corresponding to an end of the powder filling space. By pre-pressurizing the entire pressure receiving surface of the pressurizing cylinder by sequentially enlarging it, the powder is characterized in that the entire pressure receiving surface of the pressurizing cylinder is simultaneously pressurized with high-pressure pressurized liquid. Body pressure molding method.